What Is Chromatography And It's Types

Chromatography

Introduction

Chromatography is separation technique, used to separate components of a mixture using a stationary phase and mobile phase.

This technique was introduced by a Russian scientist TSWETT in 1906.by using separation of color component of leaf extract

Definition

As per IUPAC – Chromatography is a physical method of separation in which the component to be separated and distributed between two phases that one is a stationary phase and mobile phase moves in definite direction

Principle

 Chromatography mainly based on two categories

• Adsorption
• Partition

Adsorption 

 In this process analyse substance is absorbed in stationary phase.

adsorption image

Partition

1. Distribution of solute take place in 2 immiscible phases.
2. Distribution depends on partition coefficient.
3. Example- take oil and water add another substance the distribution of substance is depend on the partition coefficient of oil and water

partition coefficient
it is determined by the ability of solute to be partitioned be two immiscible liquids.

Formula

Kd=concentration of solute in solvent A/

 concentrationof solute in solvent B

Types of Chromatography

There is generally two types of chromatography ie. Gas chromatography and liquid chromatography.

On the basis equilibrium process the different type of chromatography as given below

• Adsorption chromatography
• Partition chromatography
• Ion exchange chromatography
• Molecular sieve chromatography

Adsorption chromatography
The adsorption of analyte on the surface of solid stationary phase. Liquid or gas is mobile phase.

Types

• Adsorption column chromatography

• Planar chromatography or Thin layer chromatography
• Modern Planar chromatography or High performance thin layer chromatography (HPTLC)
• Gas soiled chromatography

 

Partition chromatography

This involves the distribution of solute between two phases.

Generally Liquid or gas is mobile phase. And Liquid is stationary phase.

Types

• Partition chromatography
• Paper chromatography
• Thin layer chromatography
• Liquid chromatography
• Gas liquid chromatography

Ion exchange chromatography

Involves the exchange of ions between stationary phase which is ion exchange resin and Liquid is mobile phase.

Consider as column chromatography

Molecular sieve chromatography

Also called gel chromatography

Involve separation of analtye mixture on the basis of its molecule size

Other types of chromatography

• Flash chromatography
• Supercritical fluid chromatography
• Chiral chromatography
• Ion pair chromatography
• UPLC /MPLC

APPLICATION

Chromatography has wide range of application some major given below 

1. for the identification of pharmaceuticals substance and prepratio n 
2. test for homogenity ofsubstance 
3. determination of individual substances
4. it has got excellent application in pesticide analysis
5. applicable also for the analysis of glycoside and carbohydrate

Related Questions

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Disperse system in pharmaceutics

oil in water

Disperse system

Introduction

• The disperse system refers to a system in which one substance is particularly distributed inthroughout the a second substance

• The system find wide application like

• various manfacuring process , pharmaceutical operations like- particle size redctuion, coating of drugs,microcapsulation.

Why disperse system

• The disperse system is  hetrogenous. Each of two phases exist in liquid,gas ,solid phases.

• The one  phases called is dispese phase or discontinuous phase

• The other is called dispersion medium

Component of disperse system

Three type of component occurs in disperse system as given below

• Dispersed phase –internal phase
• Dispersion medium- external phase
• Dispersing agent- for maintaining homogeneity of disperse system

Direction – the commonly known direction is “SHAKE WELL BEFORE USE”

Classification of disperse system

There are  different type of classification is available for the disperse system given blow

•  based on physical state of  disperse system
•  based on size of disperse phase
•  based on affinity of disperse phase
•  based on coarse disperse system

A) based on physical state of  disperse system

1. Suspension   
2. emuision   
3. aersol

 Suspension -state is solid/liquid Dispersion

 Emuision - liq./liq. Dispersion

 Aersol –drug either in liquid or solid form within gaseous phase

B) based on size of disperse phase

1. Molecular Dispersion
2. colloidal Dispersion 
3. coarseDispersion

Molecular Dispersion –homogenous and true solution (size-<1nm) ex.potassium ion dissolve in water

Colloidal Dispersion –intermediate between true solution and colloidal solution(size-0.5 μm -1nm) ex.collidal silver solution

Coarse Dispersion –particle invisible under ordinary light microscope(size->0.5 μm )

 C) based on affinity of disperse phase

1. Lyophilic 
2. Lyophobic

Lyophilic - Dispersed phase  has affinity towordsDispersion medium

Lyophilic - Dispersed phase  has no affinity towordsDispersion medium

D) based on coarse disperse system

1. Emulsion  Suspension
2. Emulsion - Dispersion phase is liqiud
3. Suspension - Dispersion phase is solid

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